Process for preparing tubular bodies from cellulose



Nov. 8, 1932. J. voss 1,837,446 PROCESS FOR PRBPARiNG TUBULAR BODIES FROM CELLULOSE Fil ed Sept. 5. 1928 gwvenko't;

Patented Nov. 8, 1932 UNITED STATES PAT NT OFFICE JULIUS VOSS, OF WIESBADEN-BIEBRICH, GERMANY, ASSIGNOR, BY MESN E ASSIGN- MENTS, TO THE VISKING CORPORATION, OF CHICAGO, ILLINOIS, .A. CORPORATION OF VIRGINIA rnoons's FOR PREPARING TUBULAR BODIES, rnoivr oEIiLULosE Application filed September 5, 1928,8eria1 No.

My present invention relates to a process for preparing tubular bodies from cellulose.

The manufacture of tubular bodies from 5 cellulose has hitherto been carried out by causing cellulose solutions, especially viscose, to flow from an annular nozzle into a precipitating bath and then conducting the tubular body thus obtained in the form of a flattened band through the successive cleaning baths. The latter are generally contained in large vats provided with two superposed series of rollers which effect the transport of the band. The lower set of rollers lies close to the bottomof the vat, whilst the upper set is just slightly covered by the liquid or lies close above its surface. The band passes alternately over an upper roller and a lower roller and remains almost all the tim in the cleaning bath.

Now this process causes considerable difliculties in the manufacture of tubular bodies, if as happens when using viscose as a starting material, in the employment of the cleaning baths, gases are formed in the interior of the tubular body, which distend it. On account of the inflation produced by the gases, the tubular body has the tendency to become distended so as to form an arcuate swelling where it passes over the upper roller in such manner that it is no longer in close contact withthe sa d roller wherebv thepassage ofthe tubular-body over the roller is, of course, greatly impeded. Moreover, the tubular body has the tendency to burst. Therefore when-working with the apparatus hitherto in use it has been necessary to discharge the gases which had collected in the body very frequently by cutting it open.

Now I have found that these difliculties can be overcome by not allowing the tubular body to run all the ,time withinthe cleaning baths, but causing it to travel great distancesoutside of the said baths, for example in such a manner that the tubular body in the distance 304,149, and in Germany September 15, 1927.

.baths.

Two preferred constructional forms of apparatus for carrying out the process according to the invention are illustrated by Way of example in Figs. 1 and 2 of the accompanying drawing.

In the apparatus shown in Fig. 1 the upper series of rollers a is arranged at a considerable heightabove the surface of the clean ing bath 1), Whilst in the apparatus shown in Fig. 2 the tubular bod a coming from the precipitating bath is rst led over two or more rollers d, e and f, g, which are not arranged too close to one another, before it returns to the cleaning bath 6. In the latter case thegases formed in the inside of the tubular body accumulate in that part .71. of

the body which is between the rollers 01,0 and f, g, whilst in the first case they accumulate in those'parts 11 of the tubular body which are situated between the upper rollers a and the bath. The result in both cases is "that inside the tubular body considerable quantities of gas can accumulate, before their removal becomes necessary. Furthermore, the tubular body passes over the upper rollers in a flat form, so that the movement ofthe tubu lar body over the said rollers ,is rendered easy. In this way the device described ren-' ders it possible to manufacture tubes of more than 500 m. length without it becoming nec essary to open the tube in orderto let out the gases; v

I have furthermore found that, by mounting the second set of rollers at a considerable height above the'cleaning bath, the number and length of the vats required for the purifying operation can be diminished owing to the surprising fact that the cleaning action of the baths continues even during the time when the tubular body is outside of the bath.

I claim:

In the process for preparing a seamless tubular body from cellulose, the new step which comprises conducting the tubular body through a bath, while gas accumulates there- 5 in, in such manner that the tubular body runs alternately inside and outside of the bath, the distance the tubular body travels on the outside of the bath in each instance being at least approximately as long as the distance it i m travels inside the bath between its travels outside the bath.

In testimony whereof, I affix my signature.

, JULIUS VOSS. 

